Peelable atraumatic tip and body for a catheter or sheath

ABSTRACT

A splittable/peelable tubular body ( 2 ) of a catheter or sheath wherein the tubular body ( 2 ) has a splittable/peelable atraumatic tip ( 14 ) is disclosed. The atraumatic tip ( 4 ) is generally softer than the tubular body ( 2 ). The tubular body ( 2 ) and atraumatic tip ( 4 ) each comprise a peel mechanism longitudinally extending along their respective lengths. The peel mechanisms are formed by longitudinally extending regions of interfacial bonding ( 11 ) between first and second longitudinally extending strips ( 8, 10 ) of polymer material. Each strip ( 8, 10 ) forms at least a portion of an outer circumferential surface of the tubular body ( 2 ) and atraumatic tip ( 4 ). A region of stress concentration extends along the region of interfacial bonding. The stress concentration facilitates the splitting of the tubular body ( 2 ) and atraumatic tip ( 4 ) along their respective peel mechanisms.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. provisional patentapplication No. 60/675,973 (“the '973 application”), which was filed on28 Apr. 2005; and the present application also claims priority to U.S.provisional patent application No. 60/677,423 (“the '423 application”),which was filed on 3 May 2005. This application is also related tointernational patent application no. PCT/US2006/16373, entitled “TubularBody for a Catheter or Sheath” being filed concurrently herewith (the'373 application). The '973, '423, and '373 applications are herebyincorporated by reference as though fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to bodies for catheters and sheaths, andto tips for use in conjunction with such catheters and sheaths, as wellsas to methods of manufacturing and using the same. More particularly,the present invention relates to splittable and radiopaque bodies andtips, and to methods of manufacturing and using such bodies and tips.

Catheters and sheaths are commonly manufactured with splittable (i.e.,peelable or peel-away) type tubular bodies that allow the catheter orsheath to be removed from about an implanted medical device (e.g.,pacemaker leads) without disturbing the device. Prior art tubular bodiesare formed with peeling grooves that extend longitudinally along theinner or outer circumferential surfaces of their walls in order to makethe tubular bodies splittable. Providing such peeling grooves is adifficult and expensive manufacturing process.

Other catheters and sheaths are commonly manufactured with tubularbodies having radiopaque distal tips. Such catheters and sheaths areused in cardiovascular procedures and other medical procedures. Theradiopaque distal tip may be viewed within a patient's body via an X-rayfluoroscope or other imaging system, thereby allowing a physician toposition the tubular body as required during a procedure.

Prior art tubular bodies with radiopaque distal tips often use preciousheavy metals (e.g., gold, platinum, tantalum) to achieve sufficient tipradiopacity. For example, a thin band of a precious heavy metal isimbedded in the distal tip of each such prior art tubular body. As aresult, such prior art tubular bodies end up being quite expensivebecause of the high cost of the precious heavy metals and the laborintensive manufacturing processes used to manufacture such tubularbodies.

Tubular bodies are made from polymeric materials that may not bechemically compatible with the precious metal used to form theradiopaque distal band. As such, the distal band may not adhere to thematerial matrix of the tubular body, causing potential materialseparation and a discontinuity in mechanical strength.

Where a tubular body with a radiopaque distal tip also needs to besplittable to allow its removal from a patient without disturbing animplanted medical device, the thin band of precious heavy metal must beprovided with a peeling groove that coincides with the peeling groove inthe tubular body's wall. This adds further difficulty and expense to analready difficult and expensive manufacturing process.

There is a need in the art for a splittable and/or radiopaque tubularbody that utilizes less costly materials, is less labor intensive tomanufacture, and is less likely to fail during a medical procedure dueto material separation. There is also a need for methods ofmanufacturing and using such a tubular body.

BRIEF SUMMARY OF THE INVENTION

The present invention, in one embodiment, is a peelable atraumatic tipfor a peelable body of a catheter or sheath. The tip comprises a peelmechanism longitudinally extending along the tip. The tip may begenerally softer than the body.

In one embodiment, the peel mechanism is formed by a longitudinallyextending region of interfacial bonding between first and secondlongitudinally extending strips of material. The material of the firststrip may have a greater amount of radiopaque filler than the polymermaterial of the second strip. Each strip may form at least a portion ofan outer circumferential surface of the tubular body. A region of stressconcentration extends along the region of interfacial bonding. Thestress concentration facilitates the splitting of the tip along the peelmechanism.

In another embodiment, the materials of the first and second stripsdiffer in that the material of the first strip is loaded with a greateramount of inorganic filler than the material of the second strip. Thematerial of the first strip may comprise a greater amount of radiopaquefiller than the material of the second strip.

In yet another embodiment, a polymeric material of the first strip isnot chemically compatible with a polymeric material of the second strip.Consequently, a polymer compatibilizer is introduced into at least oneof the polymer materials to improve melt adhesion between the first andsecond strips of polymer material.

In one embodiment, the peel mechanism is formed by a peel groove. Thepeel mechanism may be formed, for example, by a score/skive line. Thetip may further comprise a circular radiopaque band imbedded below anouter circumferential surface of the tip. The band includes a notchaligned with the peel mechanism.

In another embodiment, the tip also includes third and fourthlongitudinally extending strips of material. In this embodiment thethird strip has a greater amount of radiopaque filler than the fourthstrip and the third strip is wider than the first strip.

The present invention, in yet another embodiment, is a method ofattaching a peelable atraumatic tip to a distal end of a peelabletubular body of a catheter or sheath. The method comprises placing thetubular body on a mandrel, and placing the tip onto the distal end ofthe body. The body includes a first peel mechanism longitudinallyextending along the body, and the tip includes a second peel mechanismlongitudinally extending along the tip. The second peel mechanism isaligned to longitudinally coincide with the first peel mechanism. Thetip is joined to the distal end of the body.

In one embodiment, the second peel mechanism is formed by alongitudinally extending region of interfacial bonding between first andsecond longitudinally extending strips of material. The second peelmechanism may be formed by a peel groove. Alternatively, the second peelmechanism may be formed by a score/skive line.

The present invention, in one embodiment, is a catheter or sheathcomprising a splittable tubular body and a splittable atraumatic tip.The splittable tubular body includes a first peel mechanismlongitudinally extending along the body. The splittable atraumatic tipincludes a second peel mechanism aligned with the first peel mechanismand longitudinally extending along the tip. The second peel mechanism isformed by a longitudinally extending region of interfacial bondingbetween first and second longitudinally extending strips of material.

The present invention, in one embodiment, is a catheter or sheathcomprising a splittable tubular body and a splittable atraumatic tip.The splittable tubular body includes a first peel mechanismlongitudinally extending along the body. The first peel mechanism isformed by a longitudinally-extending region of interfacial bondingbetween first and second longitudinally extending strips of material.The splittable atraumatic tip includes a second peel mechanism alignedwith the first peel mechanism and longitudinally extending along thetip.

The present invention, in one embodiment, is a splittable device forcoupling to a proximal end of a splittable tubular body for a catheteror sheath. The device comprises a housing including a split line formedby a longitudinally extending region of interfacial bonding betweenfirst and second longitudinally extending strips of polymer material. Invarious embodiments, the device is, for example, an interlock, a valve,a junction, or a fitting.

The present invention, in yet another embodiment, is a method ofattaching an atraumatic tip to a distal end of a tubular body of acatheter or sheath. The method is as follows. The tubular body isprovided and caused to have a first pre-curved portion existing in afirst plane. The tip is provided and includes a first radiopaque striplongitudinally extending along the tip and existing in a second plane.The tip is placed onto the distal end of the body such that the firstand second planes align, and the tip is joined to the distal end.

The present invention, in another embodiment, is a catheter or sheathincluding a tubular body and an atraumatic tip coupled to the distal endof the body. The tubular body includes a first pre-curved portionexisting in a first plane. The atraumatic tip includes a firstradiopaque strip longitudinally extending along the tip and existing inthe first plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of the present invention according to afirst embodiment, including 1 e/peelable tubular body for a catheter orsheath, wherein the tubular body includes a distal end and a proximalend and is formed of at least two integral longitudinal strips ofdifferent material.

FIG. 2A is a latitudinal cross-sectional view of the first embodiment ofthe tubular body taken through section line A-A in FIG. 1.

FIG. 2B is a longitudinal cross-sectional view of the first embodimentof the tubular body taken through section line A′-A′ in FIG. 2A.

FIG. 3 is a side elevation view of the present invention according to asecond embodiment, including a splittable tubular body for a catheter orsheath, wherein the tubular body includes a distal end and a proximalend and is formed of at least two integral longitudinal strips ofdifferent material.

FIG. 4A is a latitudinal cross-sectional view of the second embodimentof the tubular body taken through section line B-B in FIG. 3.

FIG. 4B is a longitudinal cross-sectional view of the second embodimentof the tubular body taken through section line B′-B′ in FIG. 4A.

FIG. 4C is a latitudinal cross-sectional view of a first variation ofthe second embodiment of the tubular body taken through section line B-Bin FIG. 3.

FIG. 4D is a longitudinal cross-sectional view of the first variation ofthe second embodiment of the tubular body taken through section lineB″-B″ in FIG. 4C.

FIG. 4E is a latitudinal cross-sectional view of a second variation ofthe second embodiment of the tubular body taken through section line B-Bin FIG. 3.

FIG. 4F is a longitudinal cross-sectional view of the second variationof the second embodiment of the tubular body taken through section lineB″′-B″′ in FIG. 4E.

FIG. 5 is a side elevation view of the present invention according to athird embodiment, including a splittable tubular body for a catheter orsheath, wherein the tubular body includes a distal end and a proximalend and is formed of at least two integral longitudinal helical stripsof different material.

FIG. 6A is a latitudinal cross-sectional view of the third embodiment ofthe tubular body taken through section line C-C in FIG. 5.

FIG. 6B is a longitudinal cross-sectional view of the third embodimentof the tubular body taken through section line C′-C′ in FIG. 6A.

FIG. 7 is a side elevation view of the present invention according to afourth embodiment, including a splittable tubular body for a catheter orsheath, wherein the tubular body includes a distal end and a proximalend and is formed of at least two integral longitudinal helical stripsof different material.

FIG. 8A is a cross-sectional view of the fourth embodiment of thetubular body taken through section line D-D in FIG. 7.

FIG. 8B is a longitudinal cross-sectional view of the fourth embodimentof the tubular body taken through section line D′-D′ in FIG. 8A.

FIG. 8C is a latitudinal cross-sectional view of a first variation ofthe fourth embodiment of the tubular body taken through section line D-Din FIG. 7.

FIG. 8D is a longitudinal cross-sectional view of the first variation ofthe fourth embodiment of the tubular body taken through section lineD″-D″ in FIG. 8C.

FIG. 8E is a latitudinal cross-sectional view of a second variation ofthe fourth embodiment of the tubular body taken through section line D-Din FIG. 7.

FIG. 8F is a longitudinal cross-sectional view of the second variationof the fourth embodiment of the tubular body taken through section lineD″′-D″′ in FIG. 8E.

FIG. 9 is similar to FIG. 2A, but is a cross-sectional view of thepresent invention according to a fifth embodiment, including asplittable tubular body, wherein the tubular body has integral peelgrooves that can be located in either the first or the secondlongitudinal strips.

FIG. 10 is a longitudinal section elevation of the tubular body with anatraumatic tip.

FIG. 11 is an enlarged, cross-sectional view of the portion of FIG. 10shown in dashed lines on that figure.

FIG. 12 is an enlarged, side elevation view of the distal end of thetubular body prior to the attachment of the tip.

FIG. 13 is an isometric view of an atraumatic tip including a pair ofwide high-radiopacity strips and a pair of narrow high-radiopacitystrips.

FIG. 14 is a distal end view of the atraumatic tip depicted in FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a side elevational view of the present invention according toa first embodiment, including a splittable (i.e., peel-away type)tubular body 2 for a catheter or sheath. The tubular body 2 includes adistal end 4 and a proximal end 6. In the embodiment shown in FIG. 1,the tubular body 2 is formed of at least two integral longitudinalstrips 8, 10 of different materials, (e.g., a first polymer and a secondpolymer). As indicated in FIG. 1, each strip 8, 10 may extend the fulllength of the tubular body 2 in a generally straight manner.

The strips 8, 10 will be referred to herein as the first strip 8 and thesecond strip 10. The material of the first strip 8 will be sufficientlydifferent from the material of the second strip 10 so as to form astress concentration along the interfacial zones (i.e., borders) 11between the two strips 8, 10. The stress concentration forms a peel line11 that acts like a built-in peel groove. As a result, the tubular body2 may be readily splittable although it lacks an actual peel groove.

The dissimilarity between the materials used to form the strips 8, 10need only be sufficient enough to create a stress concentration thatacts as a built-in peel groove. This may be accomplished in differentways, including the following ways.

The materials used for the strips 8, 10 may be from a first polymer, andthe second strip 10 may be constructed from a second polymer, generallythe same, but can also differ. The polymer used for the first strip 8may have a different molecular orientation than the polymer used for thesecond strip 10. In one embodiment, the polymer material used for thefirst strip 8 is a polymer with flow-induced axial molecularorientation, and the polymer used for the second strip 10 is a polymerhaving little or no flow-induced axial molecular orientation. In such anembodiment, the tear strength along the flow-induced orientationdirection for the polymeric material used for the first strip 8 willdecrease due to the mechanical anisotropy induced by the molecular chainalignment. Conversely, due to its low level of mechanical anisotropy,the polymeric material used for the second strip 10 will have any one orall of the following attributes: high tear strength; high mechanicalstrength, high torquability; and high kink resistance. Examples ofmaterials that can be used for the first strip 8 and are easilymolecularly oriented along the flow direction during polymer processinginclude, among other materials, crystal polymers like Ticona Vectra™,LKX 1107, and LKX 1113.

The base polymer materials used for the first and second strips 8, 10can be chemically the same or similar, except, the material used for thefirst strip 8 is loaded with semi-compatible or incompatible inorganicfillers. Such fillers include radiopaque fillers or othergeneral-purpose fillers like silica, clay, graphite, mica, and calciumcarbonate. In such an embodiment, the tear strengths and the elongationsat yield and break for the material used for the first strip 8 willdecrease with the increase of the filler loading.

The base polymeric materials used for the first and second strips 8, 10can be chemically-compatible. A polymer compatibilizer is introduced toat least one of the polymer materials used for the first and secondstrips 8, 10 to improve the melt adhesion between the first and secondstrips 8, 10.

After the tubular body 2 is manufactured, the material used for thefirst strips 8 can be different from the material used for the secondstrip 10 with respect to molecular orientation and/or anisotropy inmechanical properties. This will especially be the case with respect totear strength and elongation at yield and break. Furthermore, thematerials used for the first and second strips 8, 10 will be at leastpartially compatible such that self-adhesion interfacial zones 11 arereliably formable between the strips 8, 10.

The polymer materials used for the strips 8, 10 can be functionallymiscible. To be functionally miscible, the two materials used for thestrips 8, 10, must have sufficient adhesion to function for the intendeduse of the instrument, but must have sufficient stress concentrationsformed at the interfacial zones 11 between the strips 8, 10 to readilyact as a built-in peel groove when the instrument has completed itsintended function. In another embodiment, the materials used for thestrips 8, 10 are chemically miscible or partially miscible in order toimpose the self-adhesion of the strips 8, 10 and create reliableinterfacial regions 11 between said strips 8, 10. In one embodiment, thematerials used for the strips 8, 10 include melt-processablethermoplastics (e.g., polyethylene, polyvinylidene fluoride, fluorinatedethylene-propylene copolymer, Polyethylene-co-tetrafluoroethylene,polypropylene, polyamide-6, polyamide-6.6, polyamide-11, polyamide-12,polyethylene terephathlate, polybutylenes terephathlate, polycarbonates,polystyrene, etc.) and thermoplastic elastomers (“TPEs”) (e.g.,polyamide-based TPEs, olefinic TPEs, ionic TPEs, polyester-based TPEs,thermoplastic polyurethanes, etc.).

The polymer material used for the first strip 8 can be a material highlyloaded with a radiopaque material. In such an embodiment, the firststrip 8 is referred to as the high radiopacity strip(s) 8. In the sameembodiment, the material used for the second strip 10 is a polymermaterial that is not loaded or a material that is lightly loaded with aradiopaque material. In such an embodiment, the second strip 10 isreferred to as the low radiopacity strip(s) 10.

As will described in greater detail later in this Detailed Description,the tubular body 2 is inserted into the body of a patient via a surgicalsite (e.g., entering the chest cavity below the xiphoid process) anddirected to a point of treatment (e.g., the pericardial space of aheart). Alternatively, the tubular body 2 is inserted into the body of apatient via a body lumen of a patient (e.g., a blood vessel) andmanipulated so it travels along the body lumen to a point of treatment(e.g., a chamber in the heart). A medical device is implanted at thepoint of treatment via the tubular body 2. To allow the removal of thetubular body 2 without disturbing the implanted medical device (e.g.,pacemaker leads), the tubular body 2 is longitudinally split along theinterfaces 11 between the strips 8, 10 by simply forcing the sides ofthe tubular body 2 apart via a fingernail, tool or other implement. Thestress concentrations 11 formed at the interfaces 11 between the strips8, 10 act as a built-in peel groove. The split tubular body 2 is thenremoved from about the implanted medical device.

Where the tubular body 2 includes a first strip 8 formed from a materialthat is highly-loaded with a radiopaque material (i.e., the first strip8 is a high radiopacity strip 8), the travel and positioning of thetubular body 2 within the patient may be monitored via X-rayfluoroscopy.

As will become evident from this Detailed Description, the splittabletubular body 2 in its various embodiments provides the followingadvantages. First, the tubular body 2 is readily splittable between thetwo types of strips 8, 10 without the presence of a peeling groove,score or skive. Second, the tubular body 2 is less expensive tomanufacture than prior art splittable tubular bodies because a peelgroove does not need to be formed on the tubular body 2, and the tubularbody 2 can be made in a single simple process, such as co-extrusion,co-injection molding, or co-compression molding.

In embodiments of the tubular body 2 that have first strips 8 made ofmaterials that are highly-loaded with radiopaque materials (i.e.,tubular bodies 2 with high radiopacity strips 8), such tubular bodies 2will also have the following advantages. First, because the tubular body2 is visible in the human body along its entire length via an X-rayfluoroscope, a physician does not need to estimate the position of theextreme end of the distal tip 4 as is required with prior art tubularbodies that have radiopaque rings implanted in their distal ends.Second, because the tubular body 2 is made from compatible polymers orpolymeric compounds without the use of pure metals or metalliccompounds, the tubular body 2 has better material compatibility andmechanical integrity than prior art tubular bodies. Third, by having atubular body 2 with both high radiopacity strips 8 and low radiopacitystrips 10, the tubular body is highly flexible, yet highly kinkresistant. Other advantageous aspects of the tubular body 2 will becomeapparent throughout this Detailed Description.

For a better understanding of the first embodiment of the tubular body 2and its strips 8, 10, reference is now made to FIGS. 2A and 2B. FIG. 2Ais a cross-sectional view of the first embodiment of the tubular body 2taken through section line A-A in FIG. 1. FIG. 2B is a longitudinalcross-sectional view of the first embodiment of the tubular body 2 takenthrough section line A′-A′ in FIG. 2A. As shown in FIGS. 2A and 2B, thefirst embodiment of the tubular body 2 includes a wall 12 that has anouter circumferential surface 14 and an inner circumferential surface16. The outer circumferential surface 14 forms the outer surface of thetubular body 2 and the inner circumferential surface 16 defines a lumen18 through the tubular body 2 that runs the full length of the tubularbody 2.

As illustrated in FIG. 2A, each strip 8, 10 forms an integral segment ofthe wall 12. As shown in FIG. 2A, the tubular body 2, in one embodiment,may have four first strips 8 and four second strips 10 that are formedtogether (e.g. under a co-extrusion process) to create a wall 12 that iscircumferentially continuous and integral along its entire length. Inother embodiments, there will be as few as one first strip 8 and onesecond strip 10. In yet other embodiments, there will be any number ofeach type of strip 8, 10, including more than four first strips 8 andfour second strips 10. Also, in some embodiments, one type of strip 8,10 will outnumber the other type of strip 8, 10.

In one embodiment with two first strips 8 and two second strips 10, eachstrip 8, 10 will have a width that comprises approximately 25% of thecircumference of the tubular body wall 12. In other embodiments wherethe strips 8, 10 each account for generally equal percentages of thecircumference of the tubular body wall 12, the width of the strips 8,10, depending on the total number of strips, will range betweenapproximately 2% and approximately 50% of the circumference of thetubular body wall 12.

In one embodiment, one type of strip 8, 10 may constitute a greaterpercentage of the circumference of the tubular body wall 12. In otherwords, the first strips 8 may have greater widths than the second strips10, or vice versa. For example, as illustrated in FIG. 2A, each of thefour first strips 8 account for approximately 17% of the circumferenceof the tubular body wall 12, while each of the second strips 10 eachaccount for approximately 8% of the circumference of the tubular bodywall 12. Similarly, in another embodiment with two first strips 8 andtwo second strips 10, each of the two second strips 10 accounts forapproximately 33% of the circumference of the tubular body wall 12,while each of the two first strips 8 accounts for approximately 17% ofthe circumference of the tubular body wall 12. Again, depending on thenumber of strips 8, 10, in other embodiments, the width of the strips 8,10 may range between approximately 2% and approximately 50% of thecircumference of the tubular body wall 12. In other embodiments, thewidth of one or more of the strips 8, 10 will be between approximately0.1% and approximately 5% to form a micro strip 8, 10.

In one embodiment, one or more of the strips 8, 10 may have a uniquepercentage of the circumference of the tubular body wall 12. Forexample, in an embodiment of the tubular body 2 having multiple firststrips 8, at least one (if not all) of the first strips 8 has a uniquewidth. Thus, in one embodiment, the widths 8 of the first strips are notall equal. In other embodiments, a similar configuration could exist forat least one (if not all) of the second strips 10 or at least one (ifnot all) of the strips 8, 10.

In one embodiment, the lumen 18 will have a diameter of betweenapproximately 4 French (“F”) and approximately 22 F. In one embodiment,the tubular body 2 will have an outer diameter of between approximately5 F and approximately 24 F. In one embodiment, the tubular body 2 willhave a wall with a thickness of between approximately 0.006″ andapproximately 0.026″.

For a discussion of a second embodiment of the invention, reference isnow made to FIGS. 3, 4A and 4B. FIG. 3 is a side elevation view of asecond embodiment of the radiopaque tubular body 2 having a distal end 4and a proximal end 6 and being formed of at least two integrallongitudinal strips 8, 10. In one embodiment, these strips 8, 10 havedifferent radiopacities. FIG. 4A is a latitudinal cross-sectional viewof the second embodiment of the tubular body 2 taken through sectionline B-B in FIG. 3. FIG. 4B is a longitudinal cross-sectional view ofthe second embodiment of the tubular body 2 taken through section lineB′-B′ in FIG. 4A.

As can be understood from FIG. 3 and as is more readily seen in FIGS. 4Aand 4B, the second embodiment of the tubular body 2 and its strips 8, 10are configured similarly to those in the first embodiment of the tubularbody 2 as depicted in FIGS. 1, 2A and 2B, except the first strips 8 ofthe second embodiment are subjacent to layers of second strip material10′, 10″ that form the outer and inner circumferential surfaces 14, 16of the tubular body wall 12. In other words, as illustrated in FIGS. 3,4A and 4B, the first strips 8 of the second embodiment of the tubularbody 2 are sandwiched between an outer layer 10′ and an inner layer 10″of second strip material 10.

In other variations of the second embodiment, the first strips 8 of thesecond embodiment of the tubular body 2 are subjacent to a single layerof second strip material 10. For example, in a first variation of thesecond embodiment of the tubular body 2, as depicted in FIGS. 4C and 4D,which are, respectively, a latitudinal cross-sectional view of thetubular body 2 taken through section line B-B in FIG. 3 and alongitudinal cross-sectional view of the tubular body 2 taken throughsection line B″-B″ in FIG. 4C, the first strips 8 are subjacent to asingle layer of second strip material 10, which is an outer layer 10′.Thus, as depicted in FIGS. 4C and 4D, the second strip outer layer 10′forms the outer circumferential surfaces 14 of the tubular body wall 12and the first strips 8 form segments of the inner circumferentialsurface 16 of the tubular body wall 12.

Similarly, in a second variation of the second embodiment of the tubularbody 2, as depicted in FIGS. 4E and 4F, which are, respectively, alatitudinal cross-sectional view of the tubular body 2 taken throughsection line B-B in FIG. 3 and a longitudinal cross-sectional view ofthe tubular body 2 taken through section line B″′-B″′ in FIG. 4E, thefirst strips 8 are subjacent to a single layer of second strip material10, which is an inner layer 10″. Thus, as depicted in FIGS. 4E and 4F,the second strip inner layer 10″ forms the inner circumferentialsurfaces 16 of the tubular body wall 12 and the first strips 8 formsegments of the outer circumferential surface 14 of the tubular bodywall 12.

For a discussion of a third embodiment of the invention, reference isnow made to FIGS. 5, 6A and 6B. FIG. 5 is a side elevation view of athird embodiment of the tubular body 2 having a distal end 4 and aproximal end 6 and being formed of at least two integral longitudinalhelical strips 8, 10. These strips 8, 10 can have differentradiopacities. FIG. 6A is a latitudinal cross-sectional view of thethird embodiment of the tubular body 2 taken through section line C-C inFIG. 5. FIG. 6B is a longitudinal cross-sectional view of the thirdembodiment of the tubular body 2 taken through section line C′-C′ inFIG. 6A.

As shown in FIGS. 5, 6A and 6B, in the third embodiment of the tubularbody 2, its strips 8, 10 are configured similarly to those in the firstembodiment of the tubular body 2 as depicted in FIGS. 1, 2A and 2B,except the strips 8, 10 of the second embodiment extend spirally orhelically along the length of the third embodiment of the tubular body2.

For a discussion of a fourth embodiment of the invention, reference isnow made to FIGS. 7, 8A and 8B. FIG. 7 is a side elevation view of afourth embodiment of the tubular body 2 having a distal end 4 and aproximal end 6 and being formed of at least two integral longitudinalhelical strips 8, 10. These strips 8, 10 can have differentradiopacities. FIG. 8 is a latitudinal cross-sectional view of thefourth embodiment of the tubular body 2 taken through section line D-Din FIG. 7. FIG. 8B is a longitudinal cross-sectional view of the fourthembodiment of the tubular body 2 taken through section line D′-D′ inFIG. 8A.

As can be understood from FIG. 7 and as is more readily seen in FIGS. 8Aand 8B, the fourth embodiment of the tubular body 2 and its helicalstrips 8, 10 are configured similarly to those in the third embodimentof the tubular body 2 as depicted in FIGS. 5, 6A and 6B, except thehelical first strips 8 of the fourth embodiment are subjacent to layersof second strip material 10′, 10″ that form the outer and innercircumferential surfaces of the tubular body wall 12. In other words, asillustrated in FIGS. 7, 8A and 8B, the helical first strips 8 of thefourth embodiment of the tubular body 2 are sandwiched between an outerlayer 10′ and inner layer 10″ of second strip material 10.

In other variations of the fourth embodiment, the first strips 8 of thefourth embodiment of the tubular body 2 are subjacent to a single layerof second strip material 10. For example, in a first variation of thefourth embodiment of the tubular body 2, as depicted in FIGS. 8C and 8D,which are, respectively, a latitudinal cross-sectional view of thetubular body 2 taken through section line D-D in FIG. 7 and alongitudinal cross-sectional view of the tubular body 2 taken throughsection line D″-D″ in FIG. 8C, the first strips 8 are subjacent to asingle layer of second strip material 10, which is an inner layer 10″.Thus, as depicted in FIGS. 8C and 8D, the second strip inner layer 10″forms the inner circumferential surface 16 of the tubular body wall 12and the first strips 8 form segments of the outer circumferentialsurface 14 of the tubular body wall 12.

Similarly, in a second variation of the fourth embodiment of the tubularbody 2, as depicted in FIGS. 8E and 8F, which are, respectively, alatitudinal cross-sectional view of the tubular body 2 taken throughsection line D-D in FIG. 7 and a longitudinal cross-sectional view ofthe tubular body 2 taken through section line D″′-D″′ in FIG. 8E, thefirst strips 8 are subjacent to a single layer of second strip material10, which is an outer layer 10′. Thus, as depicted in FIGS. 8E and 8F,the second strip outer layer 10′ forms the outer circumferential surface14 of the tubular body wall 12 and the first strips 8 form segments ofthe inner circumferential surface 16 of the tubular body wall 12.

The first strips 8 and the second strips 10 can be formed from twocompatible polymers or polymeric compounds into an integral tubular body2 via co-extrusion, co-injection molding, or co-compression moldingprocesses. Candidate polymeric materials include thermoplastic andthermosetting polymer systems.

The first strips 8 may be formed of material that is heavily filled witha biocompatible filler of heavy metal or a biocompatible metalliccompound that gives rise to high radiopacity under X-ray radiation. Thefunctional width and wall thickness (i.e., percentage of thecircumference of the tubular body wall 12) necessary for visibility viaX-ray fluoroscopy will vary depending on the degree of radiopacity for afirst strip 8 (i.e., high radiopacity strip 8). For example, where afirst strip 8 has a high degree of radiopacity (due to the radiopaquenature of the filler of metal or metallic compound impregnated in thepolymer and/or due to the percentage of the metal or metallic compoundin the polymer), narrower and thinner first strips 8 will suffice. Onthe other hand, where a first strip 8 has a lower degree of radiopacity,wider and thicker first strips 8 will be required to achieve thenecessary visibility via X-ray fluoroscopy.

The first strips 8 (i.e., high radiopacity strips 8), if they are madefrom elastomeric polymer materials loaded with radiopaque fillers,provide kink resistance for the tubular body 2 in addition to providingthe ability to be visualized within a patient's body via X-rayfluoroscopy. In a preferred embodiment, the first strips 8 will be atungsten-impregnated thermoplastic elastomer, including thermoplasticpolyurethane, polyether block amide, and etc. The amount of tungstenused will depend on the degree of radiopacity required and thethermoplastic elastomer. For example, when the strips are formed ofPEBAX, the first strip can be loaded with 60-5% by weight tungsten, andpreferably 80-85% by weight tungsten.

The second strips 10 (i.e., low radiopacity strips 10) are either notloaded with radiopaque fillers or are lightly loaded. Thus, the secondstrips 10 have a low radiopacity under X-ray radiation and providemechanical strength and durability for the tubular body 2.

For melt processing purposes, the selection of the pairs of polymersused for the strips 8, 10 is primarily based on the level of chemicalcompatibility, balance of mechanical properties, and melt processabilitybetween the pairs of polymers. Different grades of polymers having thesame constituent chemical species (e.g., various thermoplasticelastomers, including polyether block amides, polyurethanes, olefinics,styrenics, polyesters, polyethers, and etc.) may be used for the pairs.Pairs of thermoplastics and thermoplastic elastomers can also be used(e.g., polyamides with polyether block amides, polyesters withpolyether-co-esters). Other polymer pairs are possible with use ofpolymer compatibilization technologies.

For radiopaque tubular bodies 2, one base polymer from a polymer pairmust be filled with heavy metals or metallic compounds using blendingand compounding technologies via either melt or solvent processes. Theheavy metals and compounds shall be biocompatible (e.g., barium,tungsten, tantalum, platinum, gold, bismuth, zirconium, niobium,titanium, bismuth oxychloride, barium sulfate, bismuth trioxide, iodine,iodide, etc. and their compounds). In one embodiment, the biocompatibleradiopaque filler will contain at least one element with an atomicnumber of from about 22 to about 83.

Filler of a heavy metal or a metallic compound may not be compatiblewith a selected base polymer, and may cause a drastic decrease inmechanical properties in the heavily loaded polymer compound. Toincrease the loading level of radiopaque filler and to improve thecompatibility of the filler with the base polymer, a compatibilizer orcoupling agent can be used for the polymer compound.

As previously noted, the tubular bodies 2 are peelable (i.e.,splittable) at one or more border(s) (i.e., interface(s)) between thetwo types of strips 8, 10. To longitudinally split the tubular body 2,opposite sides of the interior circumferential surface 16 are simplyforced apart via a fingernail, tool or other implement. The change inmaterial at the borders between the strips 8, 10 creates a stressconcentration point that acts as a built in peel groove along which thetubular body 2 splits when peeled. Thus, no integral peeling groove isneeded. However, in some embodiments, as indicated in FIG. 9, anintegral peel groove, skive or score 20 is provided to supplement thepeelability of the tubular body 2. This can be readily implemented inthe embodiments illustrated in FIGS. 1-4. Ideally, this peel groove,skive or score 20 is aligned longitudinally with a boarder between apair of strips 8, 10. However, the peel groove, skive or score 20 can belocated in one of the strips 8, 10 as indicated in FIG. 9. A tubularbody 2 can have one or more peel grooves, skives or scores. The peelgroove, score or skive 20 can be located in the inner and/or outercircumferential surface of the tubular body 2.

Many of the aforementioned embodiments employ at least one strip 8, 10formed of a material loaded with a radiopaque material. However, thestrips 8, 10 can be formed of polymers that are not loaded with aradiopaque or other materials. For example, the first strips 8 can beformed from a polymer that is dissimilar from the polymer forming thesecond strips 10. The dissimilarity between the two polymers forming thetwo strips 8, results in a stress concentration along the interfacialboundary between the two strips 8, 10. The stress concentration servesas a split/peel feature in the tubular body 2 for splitting/peeling thebody 2.

The polymers of the strips 8, 10 can be the same polymer, but dissimilarbecause they have dissimilar molecular orientations. The polymers of thestrips 8, 10 can be the same polymer, but dissimilar because they havedifferent toughness, hardness, rigidity, and/or etc. For example, thefirst or splitting strip 8 can be formed of PEBAX having a durometervalue of approximately 70 D, and the second or non-splitting strip 10 isformed of PEBAX having a durometer value of approximately 30-40 D.

For a discussion of an embodiment of the tubular body 2 that includes asplittable soft atraumatic tip 100, reference is now made to FIGS. 10and 11. FIG. 10 is a longitudinal section elevation of the tubular body2 with a soft atraumatic tip 100. FIG. 11 is an enlarged sectionelevation of the soft atraumatic tip 100 coupled to the distal end 4 ofthe tubular body 2 depicted in FIG. 10.

As shown in FIG. 10, the tubular body 2 can include an interlock 102coupled to the proximal end 6 and a soft atraumatic tip 100 coupled tothe distal end 4. The tubular body 2 includes one or more longitudinallyextending peel/split mechanisms 104 for facilitating thepeeling/splitting apart of the tubular body 2 to allow the removal ofthe tubular body from about an implanted medical device (e.g., pacemakerleads) without disturbing the implanted device.

The tubular body 2 can have a durometer value of approximately 70 D. Thesoft atraumatic tip 100 will have a durometer value of approximately20-40 D.

The interlock 102 has a splittable housing. In one embodiment, theinterlock 102 includes wings 106 for applying splitting forces to theinterlock 102 and causing splitting/peeling of the interlock 102, thetubular body 2 and the tip 100. The interlock 102 includes alongitudinally extending splitting mechanism 200 forming alongitudinally extending stress concentration that facilitates thesplitting of the housing of the interlock 102. In one embodiment, thesplitting mechanism 200 is a score, skive or groove 200. In oneembodiment, the splitting mechanism 200 is a strip 200 of a polymermaterial that is different from the polymer material forming the rest ofthe interlock 102. The material forming the strip 200 is different fromthe material forming the rest of the interlock in a manner similar tothose discussed in this Detailed Description with respect to the tubularbody 2 and the tip 100. The dissimilarity between the polymer of thestrip 200 and the polymer of the rest of the interlock 102 results in astress concentration extending along the interfacial zone between thetwo materials. Like the tubular body 2 and the tip 100, the stressconcentration facilitates the splitting of the interlock 200.

The strip 200 can be formed from a material that is softer than thematerial used for the rest of the interlock 102. The strip 200 can beformed from a material that is harder than the material used for therest of the interlock 102. The strip 200 and the rest of the interlock102 can be formed via polymer molding processes known in the art. Thehousing of the interlock 102 can be formed from polymers such as HighDurometer PEBAX, High Density HDPE, etc. and the split strip in thehousing is formed from polymers such as Low Durometer PEBAX, Low DensityHDPE, etc. While FIG. 10 depicts a splittable interlock 102, othermedical devices (e.g., valves, junctions, fittings, etc.) coupled to asplittable tubular body 2 can be made splittable by being provided witha splitting mechanism 200 as discussed above.

Each peel/split mechanism 104 of the tubular body 2 can be aninterfacial zone (i.e., boundary) 11 between two longitudinallyextending strips of different material 8, 10 that form a stressconcentration 11, as previously provided in detail in this DetailedDescription (see FIGS. 1 and 2A). Each peel/split mechanism 104 can be alongitudinally extending line scored/skived into the wall 12 of thetubular body 2. The scored/skived line 104 can be formed in the interiorcircumferential surface 16 of the wall 12 (e.g., see the peel groove 20in FIG. 9). The scored/skived line 104 can be formed in the exteriorcircumferential surface 14 of the wall 12. In one embodiment, thescored/skived line 104 is formed in both the exterior and interiorcircumferential surfaces 14, 16 of the wall 12.

As shown in FIG. 11, the splittable soft atraumatic tip 100 can beformed from a first soft material 110. The first material 100 can beloaded with a radiopaque filler to enhance the visibility of the tip 100during fluoroscopy. The tip 100 is bonded (e.g., reflowed) to the distalend 4 of the tubular body 2.

In order to allow the tip 100 to readily split/peel along with the body2 to allow the tubular body 2 to be removed from about an implantedmedical device (e.g., pacemaker leads), one or more peel/splitmechanisms 114 can longitudinally extend along the tip 100. Thesplit/peel mechanisms 114 are scored/skived lines 114 longitudinallyextending along the interior circumferential surface of the tip 100. Thelongitudinally extending scored/skived lines 114 can be in the exteriorcircumferential surface of the tip 100. The longitudinally extendingscored/skived lines 114 can be in both the exterior and interiorcircumferential surfaces of the tip 100.

In order to allow the tip 100 to readily split/peel along with the body2, the split/peel mechanisms 114 can be longitudinally extendinginterfaces 114 (i.e., boundaries) between longitudinally extendingstrips of first and second soft polymeric materials 110, 112.Specifically, in one embodiment, the second soft polymeric material 112is co-extruded, co-injection molded, or co-compression molded with thefirst soft polymeric material 110 in a manner similar to the processpreviously described in this Detailed Description with respect to thetubular body 2. Split/peel mechanisms 114 are formed by the interfaces114 between the first and second soft polymeric materials 110, 112.Stress concentrations 114, which facilitate the splitting/peeling of tip100, result along the interfaces 114.

In order to facilitate the splitting/peeling of the tip 100, the firstand second polymeric materials 110, 112 will differ from each other inone of the ways previously described in this Detailed Description withrespect to the tubular body 2. For example, the second polymericmaterial 112 can be a version of the first polymeric material 110 thatis heavily loaded with a radiopaque material. The first polymericmaterial 110 is PEBAX can have a durometer value of 20-40 D, and thesecond polymeric material 112 is the same type of PEBAX, except it isloaded with 75-80 percent tungsten.

Each of the strips 110, 112 can account for generally equal percentagesof the circumference of the wall of the tip 100. In one such embodiment,the width of the strips 110, 112 will depend on the total number ofstrips and will range between approximately 2% and approximately 50% ofthe circumference of the wall of the tip 100.

One type of strip 110, 112 can constitute a greater percentage of thecircumference of the wall of the tip 100. In other words, the secondstrips 112 may have greater widths than the first strips 110, or viceversa. The width of the strips 110, 112 may range between approximately2% and approximately 50% of the circumference of the wall of the tip100. In other embodiments, the width of one or more of the strips 110,112 will be between approximately 0.1% and approximately 5% to form amicro strip 110, 112.

As depicted in FIGS. 13 and 14, which are, respectively, isometric anddistal end views of an atraumatic tip 100, the atraumatic tip 100 caninclude a pair of wide high-radiopacity strips 112 a and a pair ofnarrow high-radiopacity strips 112 b. The wide high-radiopacity strips112 a run longitudinally along the tip 100 and are located 180 degreesfrom each other about the outer circumference of the tip 100. The narrowhigh-radiopacity strips 112 a run longitudinally along the tip 100 andare located 180 degrees from each other about the outer circumference ofthe tip 100.

The tip 100 is provided on a tubular body 2 of a catheter or sheathwherein the body 2 is pre-curved in two planes that are perpendicular toeach other. The tip 100 is mounted on the distal end of the body 2 suchthat the pair of wide high-radiopacity strips 112 a are coplanar with aplane in which a first curve of the body 2 exists, and the pair ofnarrow high-radiopacity strips 112 a are coplanar with a plane in whicha second curve of the body 2 exists. A physician can view the strips 112a, 112 b via fluoroscopy and, as a result, understand the orientation ofthe pre-curved portions of the tubular body 2 within the patient. Thus,the strips 112 a, 112 b facilitate the physician's proper torquing anddisplacement of the tubular body 2 within the patient to achieve optimalplacement of the distal end of the tubular body 2.

While FIGS. 13 and 14 depict a tip 100 with two pairs ofhigh-radiopacity strips 112 a, 112 b that are oriented parallel to eachother, in other embodiments the tip will have fewer or more pairs ofstrips 112 and/or the strips will have non-parallel orientationsrelative to each other. For example, the pre-curved tubular body 2 canhave a single curve plane, and the tip 100 has a single pair of highradiopacity strips 112 that corresponds to the single curve plane of thetubular body 2. The pre-curved tubular body 2 can have three or morecurve planes, and the tip 100 has three or more pairs of highradiopacity strips 112, each pair of strips 112 corresponding to arespective curve plane of the tubular body 2. The pre-curved tubularbody 2 can have curves that exist in planes that are not parallel toeach other, and the tip 100 has an equivalent number of pairs of strips112 that have the same angular relationship to each other as thecorresponding angular relationship between the corresponding curveplanes.

As can be understood from FIGS. 9-12, each peel/split mechanism 114 canbe a score/skive line used in combination with an interface/boundarybetween two strips of different material. In other words, eachinterface/boundary will be supplemented with a score/skive lineextending along the length of the interface/boundary. The score/skiveline will be located at some other location on one or more of any one ofthe strips 110, 112. There can be one or more score/skive lines. Thescore/skive lines can be located in the inner and/or outercircumferential surfaces of the tip 100.

As illustrated in FIG. 10, the split/peel mechanisms 114 of the tip 100are aligned with the corresponding split/peel mechanisms 104 of the body2. Thus, when the wings 106 of the interlock 102 are forced apart tocause the interlock 102 and body 2 to split/peel along the split/peelmechanisms 104 of the body 2, the split resulting in the wall 12 of thebody 2 propagates along the split/peel mechanisms 114 of the tip 100from the split/peel mechanisms 104 of the body 2.

To enhance the visibility of the tip 100 during fluoroscopy, a greaternumber of strips of high-radiopacity material 112 can be provided. Forexample, in one embodiment, the soft tip 100 includes one, two, three,four or more longitudinally extending strips of high-radiopacitymaterial 112. To further increase the visibility of the tip 100 duringfluoroscopy, the strips of high-radiopacity material 112 can be maderelatively wide with respect to the strips of first material 110.

To enhance the visibility of the tip 100 as compared to the visibilityof the body 2 during fluoroscopy, the number of radiopaque strips 112for the tip 100 can exceed the number of radiopaque strips 8 for thebody 2. For example, in one embodiment, the tip 100 has four radiopaquestrips 112 and the body 2 has two radiopaque strips 8. Two of the tip'sradiopaque strips 112 can be longitudinally aligned with the body's tworadiopaque strips 8. Thus, the aligned strips 8, 112 can be used aspeeling mechanisms for peeling the body and tip apart. The tip's othertwo (i.e., non-aligned) radiopaque strips 112 simply increase theradiopacity of the tip 100 and do not facilitate peeling of the tip 100.

To facilitate the ease of manufacturing a splittable tubular body 2having a splittable tip 100, the tip 100 can be provided with manypeeling mechanisms (e.g., split/peel strips 114). As a result, the tip100 can be placed on the distal end of the tubular body 2 without havingto worry about aligning the peeling mechanisms of the tip 100 with thepeeling mechanisms of the tubular body 2. This is because the largenumber of peeling mechanisms on the tip 100 assures sufficient alignmentbetween at least one of the tip peeling mechanisms and a peelingmechanism of the tubular body 2, thereby allowing the splitting of thetubular body 2 to propagate through the tip 100.

A tip 100 can have many peeling mechanisms, the tip 100 will haveapproximately four to approximately twelve split/peel strips 114 havingwidths of approximately 0.003 inches to approximately 0.025 inches. Inone embodiment, the tip 100 will have approximately eight split/peelstrips 114 having widths of approximately 0.02 inches.

As depicted in FIG. 11, in one embodiment, to enhance the visibility ofthe tip 100 during fluoroscopy, a marker band 120 formed from a highlyradiopaque material (e.g. platinum) is imbedded between the tubular body2 and the tip 100. As disclosed in U.S. patent application Ser. Nos.11/052,617 (filed Feb. 4, 2005) and 10/609,206 (filed Jun. 26, 2003),both of which are incorporated by reference into this DetailedDescription in their entireties, the marker band 120 is notched with oneor more single or double V-notches 122 to facilitate splitting of thetubular body 2, tip 100 and band 120. Each V-notch 122 is aligned with asplit/peel mechanism 114 of the tip 100. In other embodiments, the notch122 has other shapes or configurations that facilitate the splitting ofthe marker band 120 (e.g., arcuate shape, skives, slots, penetrations,etc.) In other embodiments the marker band 120 does not have a notch122, but is simply thin enough to fail where the tip 100 splits/peelswhen the tubular body 2 is being split/peeled.

The tip 100 can have a wall thickness that is generally equal to that ofthe tubular body 2. In other embodiments, the tip 100 has a wallthickness that is greater or less than the wall thickness of the tubularbody 2.

Reference is now made to FIG. 12 for a discussion of a method ofmanufacturing a splittable/peelable tubular body 2 having a softatraumatic splittable/peelable tip 100, as depicted in FIGS. 10 and 11.FIG. 12 is an enlarged side elevation view of the distal end 4 of thetubular body 2.

As can be understood from FIG. 12, a tubular body 2 having one or moresplit/peel mechanisms 104 is placed over a mandrel. The split/peelmechanisms 104 can be peel grooves or score/skive lines 114longitudinally extending along the length of the tubular body 2 aspreviously discussed in this Detailed Description. The split/peelmechanisms 104 can be interfaces/boundaries 104 formed betweenlongitudinally extending strips of co-extruded, co-injection molded, orco-compression molded first and second materials 8, 10 (see FIGS. 1-9)as previously discussed in this Detailed Description.

The distal end 4 of the tubular body 2 can be profile ground to appearas depicted in FIG. 12. Specifically, in one embodiment, the distal end4 has a distal most section 130, an intermediate section 132, and atapered section 134. In one embodiment, the distal most section 130 hasa diameter D, of approximately 0.120 inches and a length L₁ ofapproximately 0.070 inches. A step 136 transitions from the distal mostsection 130 to the intermediate section 132, which has a diameter D₂ ofapproximately 0.125 inches and a length L₂ of approximately 0.013inches. Over a length L₃ of approximately 0.057 inches, the taperedsection 134 transitions from the intermediate section 132 to thenon-ground diameter D₃ of the tubular body 2, which is approximately0.135 inches. The surface of the tapered section 134 extends at an angleσ that is approximately 5 degrees from being parallel to the surface ofthe non-ground diameter D₃ of the tubular body 2. The preceding valuesare exemplary. In other embodiments, the preceding diameters, lengthsand angles will vary without departing from the scope of the invention.

The marker band 120 can be placed about the intermediate section 132 anda portion of the tapered portion 134 such that the most distal edge ofthe marker band 120 coincides with the edge of the step 136, asindicated in FIG. 11. Each V-notch 122 of the marker band 120 is alignedwith the split/peel mechanism 104 of the tubular body 2.

A soft atraumatic splittable/peelable tip 100 is placed over the profileground portion of the distal end 4 of the tubular body 2. The tip 100can be PEBAX with a durometer value of approximately 20-40 D. This willbe considerably softer than the durometer value of the tubular body 2,which will be approximately 70 D in one embodiment.

The tip 100 can be oriented upon the distal end 4 of the tubular body 2such that the split/peel mechanisms 114 of the tip 100 are aligned tocorrespond with the split/peel mechanisms 104 of the tubular body 2. Thesplit/peel mechanisms 114 of the tip 100 can be interface/boundaries 114between co-extruded, co-injection molded, or co-compression moldedstrips of first and second polymeric materials 110, 112 that extendlongitudinally along the tip 100.

The soft tip 100 is bonded to the ground portion of the distal end 4 ofthe tubular body 2. The bonding can be performed via thermal means. Forexample, the tip 100 and tubular body 2 are supported on a mandrel and ashort section of PTFE heat shrink tube is placed over the distal end 2and the tip 100. This arrangement is then placed in a reflow-tippingmachine to bond the tip 100 to the distal end 4. In other embodiments,chemical, sonic, RF or other means are utilized to bond the tip 100 tothe distal end 4. Where a marker band 120 is present, the band 120 willbe sandwiched between the tip 100 and the tubular body 2 as shown inFIG. 11.

The split/peel mechanisms 114 of the tip 100 can be peel grooves orscore/skive lines 114 longitudinally extending along the tip 100. Insuch embodiments, the peel grooves or score/skive lines 114 will beformed during the bonding process via molding grooves in the mandrel.The peel grooves or score/skive lines 114 can be cut into the tip 100after the tip 100 has been bonded to the distal end 4. The score/skiveline depth and angle will vary depending upon the peel/split forcedesired for the tubular body 2.

The tubular body 2 with its attached tip 100 is removed from the mandreland trimmed to the correct length. A radius R of approximately 0.010inches is then ground or thermally formed in a radius die at the distalend of the tip 100 (see FIG. 11).

Many of the aforementioned embodiments of the tip 100 employ at leastone strip 110, 112 that is formed of a material loaded with a radiopaquematerial. However, the strips 110, 112 can be formed of polymers thatare not loaded with radiopaque or other materials. For example, thefirst strips 112 can be formed from a polymer that is dissimilar fromthe polymer forming the second strips 110. The dissimilarity between thetwo polymers forming the two strips 110, 112 results in a stressconcentration along the interfacial boundary between the two strips 110,112. The stress concentration serves as a split/peel feature in thetubular body 2 for splitting/peeling the body 2.

The polymers of the strips 110, 112 can be the same polymer, butdissimilar because they have dissimilar molecular orientations. Thepolymers of the strips 110, 112 can be the same polymer, but dissimilarbecause they have different toughness, hardness, rigidity, and/or etc.For example, the first or splitting strip 112 is formed of PEBAX havinga durometer value of approximately 70 D, and the second or non-splittingstrip 110 is formed of PEBAX having a durometer value of approximately20-40 D. The polymers of the strips 110, 112 are dissimilar because theyare different polymers.

A catheter or sheath employing a splittable/peelable tubular body 2 withthe described splittable/peelable soft atraumatic tip 100 isadvantageous over the prior art for several reasons. First, the tip 100can be visible via fluoroscopy. Second, the tubular body 2 ispeelable/splittable over its entire length, including its tip 100. As aresult, the tubular body 2 may be removed from about an implantedmedical device (e.g., pacemaker leads) without disturbing the medicaldevice. Third, the soft atraumatic tip 100 reduces the potential fortissue dissection, which can sometimes occur with stiffer, lessatraumatic tipped tubular bodies.

In use, a puncture is made with a thin walled needle through the skinand into a blood vessel. A guidewire is then placed through the needleinto the blood vessel and the needle is withdrawn. An intravascularintroducer is advanced over the guidewire into the lumen of the bloodvessel. The tubular body 2 is inserted into the introducer andmanipulated so it travels along the blood vessel to the point oftreatment (e.g., a chamber in the heart). The travel and positioning ofthe tubular body 2 within the patient is monitored via X-rayfluoroscopy.

In use, the tubular body 2 is inserted into the body of a patient via asurgical site (e.g., entering the chest cavity below the xiphoidprocess). A guidewire is used to direct the tubular body 2 to a point oftreatment (e.g., the pericardial space of a heart). The travel andpositioning of the tubular body 2 within the patient is monitored viaX-ray fluoroscopy.

Although the present invention has been described with reference topreferred embodiments, persons skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

We claim:
 1. A peelable atraumatic tip for a peelable body of a catheteror sheath, the tip comprising a peel mechanism longitudinally extendingalong the tip, wherein the peel mechanism is formed by alongitudinally-extending region of interfacial bonding between first andsecond longitudinally-extending strips of polymeric material.
 2. The tipof claim 1, wherein the tip is generally softer than the body.
 3. Thetip of claim 1, wherein the polymeric material of the first stripcomprises a first amount of a first radiopaque filler, wherein thepolymeric material of the second strip comprises a second amount of asecond radiopaque filler, and wherein said first amount is greater thansaid second amount.
 4. The tip of claim 3, wherein the tip has acircular cross section, with a circumference, and the first strip has awidth of between 0.1% and 5% of the circumference of the tip.
 5. The tipof claim 3, further comprising third and fourth longitudinally extendingstrips of polymeric material, wherein the polymeric material of thethird strip comprises a third amount of radiopaque filler, wherein thepolymeric material of the second strip comprises a second amount of asecond radiopaque filler, and wherein said third amount is greater thansaid fourth amount, and the third strip is wider than the first strip.6. The tip of claim 1, wherein each strip forms at least a portion of anouter surface of the tubular body.
 7. The tip of claim 1, wherein aregion of stress concentration extends along the region of interfacialbonding.
 8. The tip of claim 7, wherein the region of stressconcentration facilitates the splitting of the tip along the peelmechanism.
 9. The tip of claim 1, wherein the first polymeric materialis dissimilar from, but chemically compatible with, the second polymericmaterial.
 10. The tip of claim 1, wherein the first strip is formed of apolyether block amide having a durometer value of approximately 70 D andthe second strip is formed of a polyether block amide having a durometervalue of 20-40 D.
 11. The tip of claim 1, wherein the first polymericmaterial has a molecular orientation that is different from a molecularorientation of the second polymeric material.
 12. The tip of claim 1,wherein the first polymeric material is loaded with a greater amount ofinorganic filler than the second polymeric material.
 13. The tip ofclaim 1, wherein the first polymeric material is not chemicallycompatible with the second polymeric material, and a polymercompatibilizer is introduced into at least one of the polymericmaterials to improve melt adhesion between the first and second stripsof polymeric material.
 14. The tip of claim 1, further comprising acircular radiopaque band imbedded below an outer surface of the tip andincluding a notch aligned with the peel mechanism.
 15. A catheter orsheath comprising: a splittable tubular body including a first peelmechanism longitudinally extending along the body; and a splittableatraumatic tip including a second peel mechanism aligned with the firstpeel mechanism and longitudinally extending along the tip, wherein thesecond peel mechanism is formed by a longitudinally extending region ofinterfacial bonding between first and second continuously and integrallyjoined and longitudinally extending strips of polymer material.
 16. Thecatheter or sheath of claim 15, wherein the first peel mechanism isformed by a peel groove.
 17. The catheter or sheath of claim 15, whereinthe first peel mechanism is formed by a score/skive line.
 18. Thecatheter or sheath of claim 15, wherein the first peel mechanism isformed by a longitudinally extending region of interfacial bondingbetween third and fourth longitudinally extending strips of polymermaterial.
 19. A catheter or sheath comprising: a tubular body includinga first pre-curved portion existing in a first plane; and an atraumatictip coupled to the distal end of the body and including a firstradiopaque strip longitudinally extending along the tip and existing inthe first plane.